The present invention relates to a magnetic tape, method of manufacturing the magnetic tape, servo writer, and method of and apparatus for specifying a servo band, which contribute to specify a servo band formed on a magnetic tape.
In recent years, in order to highly accurately read out data that is recorded with high recording density from magnetic tapes such as used for backing up data of a computer system, servo signals have been recorded on a plurality of servo bands adjacent to a plurality of data tracks that are formed along a longitudinal direction of the magnetic tape. In this kind of magnetic tape, for the purpose of accurately tracing the position where the magnetic head records/reproduces on a data track, it is very important to specify which of a plurality of servo bands arranged along the width of the magnetic tape does the magnetic head positions. In a conventional method, such as disclosed in Japanese Laid-open Patent Application No.11-273040 (paragraph [0027] and FIG. 6), servo patterns of adjacent servo bands are offset along the longitudinal direction of the magnetic tape, and signals of these servo bands are read out simultaneously to compare and specify the servo band where the magnetic head positions.
However, the above conventional method requires to simultaneously compare the adjacent servo bands, which results in a drawback in that specifying the servo band can not be performed, for example, when one of the servo signals is not readout temporally or permanently due to blocking or clogging of the magnetic head. Further, because it is necessary to simultaneously compare the adjacent servo bands, a plurality of servo signal read-out elements and signal-processing circuits are necessary.
Upon writing an offset servo pattern, it is necessary to write a servo pattern on a servo band in an accurately offset manner with respect to the other servo pattern written on the reference servo band. For this reason, a gap has to be formed in an accurate position of the servo write head in accordance with the offset along the longitudinal direction of the magnetic tape. This leads to an increase in cost for manufacturing the magnetic head.
With the foregoing drawback of the prior art in view, the present invention seeks to provide a magnetic tape, method of manufacturing a magnetic tape, a servo writer, method of and apparatus for specifying a servo band, wherein specifying a servo band where the magnetic head positions can be performed without comparing servo signals written on adjacent servo bands.